Research Highlights

D. F. Webb, B. A. Emery, S. E. Gibson, I. M. Hewins, R. H. McFadden , T. A. Kuchar examine the process during which the solar magnetic field reverses polarity around solar maximum using the McIntosh Archive (McA) of solar synoptic maps over five consecutive solar cycles, SCs 19-23 or from 1955 to 2009. This data set permits us to track features such as filaments, polarity inversion lines (PILs), coronal hole (CH) boundaries and sunspots over many consecutive Carrington rotations and solar cycles.

N. M. Pedatella, E. Aa, and A. Maute explore the influence of atmospheric planetary waves on the occurrence of irregularities in the low latitude ionosphere is investigated using Whole Atmosphere Community Climate Model with thermosphere-ionosphere eXtension (WACCM-X) simulations and Global Observations of the Limb and Disk (GOLD) observations. 

Sarah Gibson et al., review the properties of an irregularly shaped “Alfvén surface” surface and discuss its importance in models of solar wind acceleration, angular momentum transport, MHD waves and turbulence, and the geometry of closed coronal loops. We also review the results of simulations and data analysis techniques that aim to determine the location of the Alfvén surface.

Kinfe Teweldebirhan, Mark Miesch, and Sarah Gibson investigate the role and impact of converging flows toward Bipolar Magnetic Regions (BMR inflows) on the Sun’s global solar dynamo. These flows are large-scale physical phenomena that have been observed and so should be included in any comprehensive solar dynamo model.

Chun-Yen Huang, Tzu-Wei Fang, Arthur Richmond, Timothy Fuller-Rowell, Jenn-Yenq Liu research expressions of newly established Rayleigh-Taylor (R-T) instability growth rates, then perform calculations using the thermospheric and ionospheric conditions based on the coupled Whole Atmosphere Model and Ionosphere Plasmasphere Electrodynamic model (WAM-IPE). The parameters used in this calculation include the field-line integrated conductivities and currents, which consider the Quasi-Dipole Coordinates and the modifications to the equations of electrodynamics.

Authors Joseph McInerney, Liying Qian, Han-Li Liu, Stanley Solomon, and Susan Nossal decided to apply the WACCM-X climate model to the upper atmosphere for the decades from the 1920s to 2010s. This type of modeling application will be useful to predict what will happen in the century ahead as greenhouse gases increase and humans make efforts to reverse the increase.

Hanli Liu, Peter Lauritzen, and Francis Vitt use the high-resolution whole atmosphere model to study small-scale wave propagation from the lower atmosphere into the thermosphere. Using this high-resolution model, which can partially resolve the small-scale waves, they can directly quantify the force exerted by these waves on the general circulation in the thermosphere.

Steven Cranmer, Rohit Chhiber, Chris Gilly, Iver Cairns, Robin Colaninno, David McComas, Nour Raouafi, Arcadi Usmanov, Sarah Gibson, Craig DeForest review the properties of Alfvén surface and discuss its importance in models of solar wind acceleration, angular momentum transport, MHD waves and turbulence, and the geometry of closed coronal loops. Simulations results and data analysis techniques are used to determine the location of the Alfvén surface.

B. Raphaldini, M. Dikpati, A. A. Norton, A. S. W. Teruya, S. W. McIntosh, C. B. Prior, and D. MacTaggart investigate how global toroid patterns and local magnetic field topology of solar active region AR12673 together can hindcast occurrence of the biggest X-flare of cycle 24. We infer that minimum-phase storms can be forecast only hours ahead, while flare-prone active regions in peak-phase can be anticipated at least a month ahead from global toroid patterns.